Optimization of CG Models - An Introduction to Computer Graphics for Artists - page 100

Chapter 8
Optimization of CG Models

8.1 Introduction

In Chap. 7 methods to help fi nd the right level of resolution for your model were
discussed. Optimization will help achieve that goal in addition to streamlining your
scene for fi nal use.
The primary goal of optimizing your model and scene is to have an effi cient fi le.
Effi cient doesn't necessarily mean “as small as possible”, though that is also a goal.
Sometimes, effi ciency demands more information in a fi le, such as in longer, more
descriptive object names within a scene. An effi cient fi le will not contain unneces-
sary information, but it will not be missing crucial information either. You do not
want to delete every triangle around a joint in a character simply because they do not
contribute to the overall shape of the object. If those triangles are used for animation
to ensure smooth limb motion, they should remain. Reducing for the sake of reduc-
tion doesn't always work. Optimizing a model is a series of compromises.
The principal compromise is between the amount of information (as little as pos-
sible) and inclusion of all necessary information. Your ability to decide what is and
what is not essential will determine your success at optimizing a fi le. If you have
insuffi cient experience or comprehension, you will probably make many errors dur-
ing optimization. Generally, it is only through trial and error that an artist learns
what is or is not needed in a fi le.

8.2 Optimization Direction

The process of derezing , or reducing the polycount of a model, presumes starting
with a high polycount object and then bringing it down to an optimized level.
Optimization can also work in the other direction. Instead of working from high
detail to low, you can work from low detail to high, adding detail until you reach